The only stupid questions are the ones that don't get asked.
You are fine using Darcy's diet
without extra supplements. In fact, one of the concerns lately is that we may be supplementing TOO much in some cases, causing liver problems.
One word of caution I would give you is that Darcy's was developed for a glider who was ill, and sometimes tends to cause healthy gliders to become a bit overweight. As long as your glider isn't getting chubby, it's fine to stay with Darcy's. But if you start noticing them looking a little chunky, you might think about switching.